A turbine machine or turbojet comprises a large number of bolted connections in the “stator” part and in the “rotor” part of the turbine machine. Some of these bolted connections are also accompanied by a shrink-fitted cylindrical connection.
These connections sometimes have to be disconnected, particularly during maintenance operations. The normal method of disassembling two flanges shrink-fitted to each other is to use extraction means such as screw sleeves to avoid damaging the flanges during disassembly. These extraction sleeves are fixed to one of the interface flanges and are used to separate the two flanges in a shrink-fitted connection.
It is known that extraction sleeves can be welded to prevent the extraction sleeve from dropping during the interference fit operation or to be sure that the torque induced by the extraction screw will be resisted by the connection between the extraction sleeve and the flange that supports it.
However, extraction sleeves welded to the flange create some difficulties. The weld of the sleeve can cause deformation of the flange in a zone close to the weld, particularly when the flanges are thin, for example of the order of a few millimeters, typically of the order of 3 to 4 millimeters.
One solution to solve the problems mentioned above consists of simply shrink-fitting the extraction sleeves in the orifices of the flanges provided for this purpose. However, with this interference fit solution, there is a risk of the sleeve slipping in the flange if this interference fit is not well sized, which would make the extraction sleeve unusable, since it would rotate in its housing during the extraction attempt, under the effects of friction of the extraction screw in the threads of the sleeve. Another problem could be damage to the sleeve if the interference fit is too strong.